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Article: IACFS/ME Ottawa CFS Conference Reports. XMRV I: XMRV's Big Test - The Blood Working Group S

Cort said:
Furthermore, despite the fact that each sample was tested multiple times by each lab no samples were found to be positive more than once.

But how can be explained that the same lab gets positive one time and negative another, provided the sample is the same?
 
But how can be explained that the same lab gets positive one time and negative another, provided the sample is the same?

I think the explanation for this is that samples were taken from each person and then each sample was divided up several times. Each lab, if I remember correctly, tested 3 or 4 samples from the same person. Because they were all essentially the same sample theoretically they should have all tested the same. (This was just another internal test of each labs effectiveness). Depending on when they did the test the WPI and Ruscetti labs, at times, stated that the same person tested positive or negative.

Since all the samples were taken from the same person at the same time - these different internal results couldn't be accounted for by the viruses disappearing from the person as in the macaque study. They are better explained by a contaminant getting into the samples sometime while they were stored in the labs.
 
Thanks for keeping it real, Cort and providing factual clarity. A lot of misinformation being posted on the blogs and forums which does not help any of us.

Its a very technical subject - I remember Lasker award winner Alter saying it was the most complex he had ever worked on! - I guess differences of opinion are to be expected particularly given XMRV's great promise.
 
Nice write up, Cort. I just want to correct one slip-up (that I feel needs correcting) in this indeed very technical subject:

- You write that Ruscetti, Lo/Alter and Hewlet (FDA) did perform culture testing. However, the Lo lab did not do culturing for the BWG study (or for their earlier study for that matter), they only did "standard" PCR. The FDA Hewlet lab did not perform one, but two seperate culturing assays (which, together with the Ruscetti lab, makes three in total). I guess the misunderstanding comes from the fact that the Lo lab is FDA too.